Ultracold atomic gases allow us to simulate bare essentials of complicated quantum phenomena, which are difficult to be resolved with other systems. Recently, so-called atomtronics devices to simulate mesoscopic transport with ultracold atomic gases have been realized in experiments. In this article, we review recent progress of two-terminal transport in ultracold atomic gases, with a special focus on point contact transport in two-component Fermi gases.
Experimental validation of the Standard Model of Particle Physics involves the measurement of the CP quantum number and couplings of the Higgs boson. Both ATLAS and CMS have reported an SM Higgs-like excess around mh=125 GeV. In this mass range the properties of the Higgs boson can be extracted from an analysis of the azimuthal angle distribution of the two jets in pp→hjj events. Instead of exploiting the jet angular correlation, we show that hadronic event shapes exhibit substantial discriminative power to separate a CP even from a CP odd Higgs. Some event shapes even show an increased sensitivity to the Higgs CP compared to the azimuthal angle correlation.
Natural environments surrounding organisms are constantly fluctuating. Biological systems achieve dynamic response functions for survival. This review shows advantages of the single-protein spectroscopy to investigate dynamic properties of chromoprotein. Fluorescence lifetime fluctuation analysis reveals a regulation mechanism of the photosynthetic light harvesting to respond to sunlight fluctuations.
We present neutron scattering under pressure in a triangular-lattice antiferromagnet that has a quantum disorder in the low-pressure phase and a noncollinear structure in the high-pressure phase. The neutron spectrum continuously evolves through critical pressure; a single mode in the disordered state becomes soft with the pressure and it splits into gapless and gapped modes in the ordered phase. Extended spin-wave theory reveals that the longitudinal and transverse fluctuations of spins are hybridized in the modes because of noncollinearity, and novel magnetic excitations are formed. We report a new hybridization of the phase and amplitude fluctuations of the order parameter near a quantum critical point in a spontaneously symmetry-broken state.
We show our recent studies on fully coupled two-fluid dynamics in superfluid 4He. In this system, the quantized vortices and the normal fluid affect each other through the mutual friction. The recent visualization experiments found strange phenomena. In the thermal counterflow, the velocity fluctuations of the laminar normal fluid is anisotropic. The fluctuations are more intense in the streamwise direction, as compared to transverse direction. The anisotropic fluctuations should be caused by the coupled dynamics of the two fluids. We performed the simulation and analyzed the velocity fluctuations of the normal fluid in the thermal counterflow. We found that the quantum turbulence causes the anisotropic velocity fluctuations. Our results are consistent with recent visualization experiments. This agreement validates the model of the coupled dynamics.